Details

In all versions of Pillow, dating back at least to the last PIL
1.1.7 release, PcdDecode.c has a buffer overflow error.

The state.buffer for PcdDecode.c is allocated based on a 3 bytes
per pixel sizing, where PcdDecode.c wrote into the buffer assuming
4 bytes per pixel. This writes 768 bytes beyond the end of the
buffer into other Python object storage. In some cases, this causes
a segfault, in others an internal Python malloc error.